Self-review fixes.

CHANGELOG.md

@@ -14,8 +14,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
-- The LineChart now has an option to not anchor the Y axis at the zero value
-  for positive and negative series that don't contain zero value.
+- The LineChart now has an option to change the behavior of the Y axis from
+  zero anchored to adaptive.
 - Lint errors reported on the Go report card.
 
 ## [0.5.0] - 21-Jan-2019

widgets/linechart/axes/scale.go

@@ -95,14 +95,16 @@ func NewYScale(min, max float64, graphHeight, nonZeroDecimals int, mode YScaleMo
 		}
 
 	case YScaleModeAdaptive:
-		// Only make the scale zero based if all the data points are equal, so
-		// we can still draw something.
+		// Even in this mode, we still anchor the axis at the zero if all the
+		// data points are equal, so we can still draw something.
 		if min > 0 && min == max {
 			min = 0
 		}
 		if max < 0 && min == max {
 			max = 0
 		}
+	default:
+		return nil, fmt.Errorf("unsupported mode: %v(%d)", mode, mode)
 	}
 	diff := max - min
 	step := NewValue(diff/float64(usablePixels), nonZeroDecimals)

widgets/linechart/axes/scale_test.go

@@ -142,6 +142,15 @@ func TestYScale(t *testing.T) {
 				{4, nil, true},
 			},
 		},
+		{
+			desc:            "fails on an unsupported Y scale mode",
+			min:             0,
+			max:             0,
+			graphHeight:     1,
+			nonZeroDecimals: 2,
+			mode:            YScaleMode(-1),
+			wantErr:         true,
+		},
 		{
 			desc:            "works without data points",
 			min:             0,

widgets/linechart/linechartdemo/linechartdemo.go

@@ -18,6 +18,7 @@ package main
 
 import (
 	"context"
+	"math"
 	"time"
 
 	"github.com/mum4k/termdash"
@@ -33,13 +34,9 @@ import (
 func sineInputs() []float64 {
 	var res []float64
 
-	/*
-		for i := 0; i < 200; i++ {
-			v := math.Sin(float64(i) / 100 * math.Pi)
-			res = append(res, v)
-		}*/
-	for i := 1600; i < 1800; i++ {
-		res = append(res, float64(i))
+	for i := 0; i < 200; i++ {
+		v := math.Sin(float64(i) / 100 * math.Pi)
+		res = append(res, v)
 	}
 	return res
 }